CriticalMacrolides×SSRI (selective serotonin reuptake inhibitor)
Updated · Methodology
Mechanism
Azithromycin is a macrolide, and its SmPC records prolonged cardiac repolarisation and QT with a risk of ventricular arrhythmia and torsade. The citalopram SmPC lists ongoing treatment with any drug capable of prolonging the QT interval among its contraindications, with no exceptions.
Symptoms
QTc prolongation on ECG, palpitations, dizziness, syncope. The end point is polymorphic ventricular tachycardia of the torsade type progressing to ventricular fibrillation. The risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, decompensated heart failure and in women.
Management
The pair sits in the citalopram SmPC contraindications, so the question is which drug stays, not how far to cut the dose. A short azithromycin course tempts one to leave things as they are, but the SSRI ban carries no exception for course length. Potassium, magnesium and QTc are checked before the start, and the antibiotic is swapped if they are off.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Zithromax (azithromycin) QT safety (2017)– ; DailyMed setid db52b91e-79f7-4cc1-9564-f2eee8e31c45
- AEMPS: Ficha técnica de Zitromax 250 mg (azitromicina) (2026)– AEMPS CIMA, nregistro 59616, revisión 09/2026, sección 4.4
- AEMPS: Ficha técnica de Seropram 30 mg (citalopram) (2024)– AEMPS CIMA, nregistro 63564, revisión 01/2024, secciones 4.2, 4.3 y 4.4